Are mosquito bites, flies, heat, cold, disturbing dreams, and nightmares that affect a Muslim considered among the matters that expiate sins and for which he is rewarded, by analogy with the noble Hadith: “No fatigue, nor disease, nor sorrow, nor sadness, nor hurt, nor distress befalls a Muslim, even if it were the prick of a thorn, but Allah expiates some of his sins thereby”?

The aforementioned Hadith is agreed upon and indicates in its generality that every harm that afflicts a Muslim in their body or soul expiates their sins and brings them good deeds. This includes the matters mentioned in the question.

Al-Nawawi said: "In these Ahadith, there is great glad tidings for Muslims, and in them is the expiation of sins through illnesses, diseases, worldly calamities, and their worries, even if their hardship is slight, and in them is the raising of ranks and the increase of good deeds."

It is stated in "Umdat al-Qari" that "nasab" (نصب) is fatigue, "wasab" (وصب) is illness, "hamm" (هم) is the disliked matter that afflicts a person, and "huzn" (حزن) is what afflicts them due to a disliked matter in the past, and these two are internal ailments. "Adha" (أذى) is what afflicts them from the transgression of others, and "ghamm" (غم) is what constricts the heart.